7. The following table gives the values of the fraction of Schottky defects, ns/N, in a crystal of NaBr, with the sodium chloride structure, as a function of temperature. Estimate the formation enthalpy of the defects. Provide plot and data analysis. (20 points) Temperature (C) Fraction of Defects 300 7.66 x 10-10 400 1.73 x 10-8 500 1.75 x 10-7 600 1.04 x 10-6 700 4.28 x 10-6